Icinga Web, Set correct write permissions for directory “/usr/local/icinga-web/app/cache”

If you have followed the Icinga install procedure through as per the installation documentation, and are having difficulty getting Icinga Web to install, you may eventually get an Agavi error saying that the cache directory is not writable (if you find the PHP errors) AgaviCacheException Failed to write cache file "/usr/local/icinga-web/app/cache/config/config_handlers.xml_production__d98552ff67d2d50d8def4e3ddb970ba8e8e151fc.php" generated from configuration file ...